How to set default value in a field?

Summary:

I am trying to set the default value of Payroll field when we hire an employee. I went to edit the page and found the field in Visual Builder studio:

Then, I am trying to follow the instructions on the documentation Oracle gives on "Set a Default Value for a Field" (link below)

Unfortunately, when I try to click on it the Value column to open a popup dialog for setting the value, the option to set a default value does not show up.

Content (please ensure you mask any confidential information):

I understand that If you see a lock, this means the field has been locked by the Default built-in rule, and you can't override it. Values that should not be overridden might be locked by Oracle.